A person who lacks the common sense to participate in any civilized conversation whatsoever but their failure to do so is tremendously hilarious. This is the person that is involved in your group for the sole purpose to get made fun of on a regular basis.

Horniest person in your group

Completely brain dead individual

Sassy to the point of hilarity

To be honest this person is just so stupid that he/she thinks that dorsal fin could possibly be an insult. I mean seriously, dolphins are one of the smartest animals that we know of today. How could anything remotely involving a dolphin be an insult?